Which are the world's most expensive cities? The cities included on this interactive map are from a 2009 study by the UBS, which tracked the ups and downs of various places in the wake of the financial crisis. Many cities have changed ranks, with som...

Most people only think that there is one way to sleep: Go to sleep at night for 6-8 hours, wake up in the morning, stay awake for 16-18 hours and then repeat. Actually, that is called a monophasic sleep cycle, which is only 1 of 5 major sleep cycles ...